Thread controller for sewing machines



Oct. 29, 1935. Q RUBEL 2,019,097

THREAD CONTROLLER FOR SEWING MACHINES Filed Jan. 29, 1934 2 Sheets-Sheet l Oct. 29, 1935. c. F. RUBEL THREAD CONTROLLER FOR SEWING MACHINES Filed Jan. 29, 1934 2 Sheets-Sheet 2 Patented Oct. 29, 1935 UNITED STATES PATENT OFFICE THREAD CONTROLLER FOR SEWING MACHINES poration of Illinois Application January 29, 1934, Serial No. 708,915

Claims.

The invention relates to new and useful improvements in a thread controlling mechanism for sewing machines, and more particularly to a needle thread controlling mechanism of the 5 type shown in my co-pending application Serial No. 603,291, filed April 5, 1932. In the machine of my prior application, the needle thread is taken up as the needle approaches the lower end of its stroke to aid in drawing up the concatenated thread loops of the previous stitch formation by a movable thread guide carried by the needle bar and a movable thread guide carried by the operating link which reciprocates the needle bar, which movable thread guides contacted with the needle thread between stationary members on which the thread rests and is guided during the thread drawing operation.

An object of the present invention is to provide an additional means operated by the needle bar and contacting with the needle thread for drawing up on the thread as the needle approaches the lower end of its stroke.

In the drawings- Figure l is a view from the front of a machine embodying the improvements with the cover plate turned to one side in order to expose the thread controlling devices associated with the needle bar;

Fig. la is a detail showing in side view the thread controlling elements operating upon the needle thread;

Fig. 2 is a view from the front of the machine at right angles to the plane of reciprocation of the needle bar and showing, in particular, the

thread controlling elements and their position relative to each other when the needle is at the upper end ofits stroke;

Fig. 3 is a view similar to Fig. 2, but showing the needle as having moved downward through the upper portion of its stroke;

Fig. 4 is a view similar to Fig. 3, but showing the needle bar well down toward the lower end of its stroke;

Fig. 5 is a diagrammatic view showing the position of the thread controlling devices when the needle is at the lower end of its stroke;

Fig. 6 is a view similar to Fig. 5, but showing the first part of the upward movement of the needle bar;

Fig. 7 is a detail taken from the side of the machine showing the position of the thread controlling members as the needle approaches the lower end of its stroke, and

Fig. 8 is a similar view showing the needle all the way down.

The invention is shown as applied to a machine of the type shown in the patent granted Norman V. Christensen and Frederick F. Zeier, March 25, 1930, No. 1,751,508. In this machine, the operating shaft is located above the work support 5 and extends in the general direction of the line of feed. The needle bar is located at the forward end of the shaft and is operated by a link connected to a crank carried by the end of the shaft. Cooperating with the needle beneath the 10 work support is a thread carrying looper which oscillates in a plane at right angles to the line of feed when entering the needle thread loop. The present invention has particularly to do with a thread controlling mechanism for the needle 15, thread in this type of machine. The needle thread is controlled by the movements of the needle bar and the link which reciprocates the needle bar. In my prior application Serial No. 603,291,. there is shown a thread controlling g0 mechanism for the needle thread wherein the moving parts are operated by the needle bar and the link which actuates the needle bar. One of these moving parts is a thread guiding eye which is rigidly attached to the needle bar. The 5 othermoving part is an arm which is attached to the link which reciprocates the needle bar so'as to project at an angle thereto. There is a stationary thread guide on the arm of the machine through which the needle thread passes 30 before entering the movable thread guides. There is also a fixed arm on the needle head which is disposed so that theneedle thread comes into contact with saidarm as the needle approaches the lower end of its stroke. Thus it is that the 35 moving thread guides are caused to take up on the needle thread after the previous needle thread loop has been dropped from the looper and while the needle is approaching the lower end of its stroke so that the previous needle 40 thread loop can be drawn up to aid in the making of a tight stitch. The link which reciprocates the needle bar moves to a vertical position when the needle is at the lower end of its stroke and this necessarily causes the thread 45 guide to reach its extreme lower position and be slightly retracted or moved upwardly just as the needle is reaching the lower end of its stroke. This modifies the extent to which the needle thread can be drawn up by these moving parts. 50

In the present machine, there is an added moving thread guide associated with these two movable thread guides referred-to above, which added thread guide continues its downward movement until the needle reaches the end of its 55 stroke, and therefore, a greater amount of thread is drawn up and a tighter stitch produced.

Referring more in detail to the drawings, the thread controlling mechanism is shown as applied to a sewing machine having a bed I carrying a work support 2. Extending upwardly from the bed I is a standard 3 carrying a needle head 4 in which the needle bar 5 reciprocates. Said needle bar is provided with a needle 6. Cooperating with this needle 6 beneath the work support is a thread carrying looper 1 of the usual type. Said thread carrying looper is mounted on a looper carrier 8 for oscillations at right angles to the line of feed, and the looper carrier 8 is in turn mounted on a looper support 9 for oscillations longitudinally of the feed for giving to the looper its needle avoiding movement.

The material is held on the work support by a presser foot H]. The machine as illustrated is provided with an English type of binder ll carried by a sliding bar 'I 2 supported by the standard 3. The manner of mounting and supporting the binder forms no part of the present invention. The machine is particularly adapted for the stitching of a binding strip to the edge of a fabno.

The looper thread is indicated at I in the drawings. Said looper thread is led from the supply through a thread guide l3, thence through a thread guide l4 at the outer end of an arm l5.

The looper thread after leaving the thread guide I4 passes through a thread guide I6, thence through a guiding tube l1 and suitable guides beneath the cloth plate to the looper.

Supported by the bracket 3 are suitable bearings in which the main actuating shaft l8 rotates. Said shaft carries a crank arm or disk l9 on which is mounted a crank 20. Cooperating with the crank 20 is a link 2|, which at its other end is attached to a stud 22 carried by the needle bar is fixed to this link 2|.

5. As the shaft 18 rotates, it will rotate the crank 20, and the crank 20, through the link 2|, will cause the needle bar to reciprocate. The thread controlling arm l5 for the looper thread This looper thread controlling mechanism per se forms no part of the present invention, but is shown and described in my co-pending application referred to above.

The present invention has particularly to do with a thread controlling mechanism for the needle thread. The thread passes from the supply through a suitable tension 23, and thence through a thread guiding eye 24 which is stationary and has no movement. Mounted on the link 2| is an arm 25. This arm 25 is secured to the link by a screw 26. There is a slot 21 in the arm, and a screw 28 passes through this slot and is threaded into the link. By loosening these screws, the arm may be adjusted to different set positions on the link. There is a limit to the range of adjustment, and in all of its set positions, the arm extends in a direction approximately at right angles to the longitudinal axis of the link. At the outer end of this arm there is an elongated thread guiding slot 29. The needle thread which is indicated at n, after passing through this thread guiding eye 24, passes through the slot 29 in the outer end of this arm.

Fixed to the needle bar is an arm 30. This arm is secured to the needle bar by a screw 3!.

Said arm is clearly shown in Fig. la. extending outwardly from the needle bar in a plane parallel with the plane of movement of the arm 25. 'At the outer end of the arm 30 is an elongated thread guiding slot 32. The needle thread 1;,

after passing through this thread slot 29 in the arm 25, then passes through the slot 32 in this arm 30. Also attached to the needle bar by this set screw 3| is an arm 33. This arm 33 and the arm 30 are preferably formed integral. The

arm 33 projects from the needle bar in a plane at right angles to the plane in which the arm 30 is located. The needle thread it after leaving the thread slot 32, passes through a thread eye 34 in the outer end of the thread arm 33.

Fixed to the needle head is a bracket 35. Said bracket is provided with slots therein through which screws 36, 36 pass for securing the bracket to the needle head so that it may be adjusted vertically on the needle head. The bracket extends around in front of the needle bar and is provided with an upstanding finger 31. Said finger 31 is located at the outer end of the bracket, and adjacent the base of the finger is a shoulder 38. The needle thread n after leaving the thread eye 34, passes down alongside of the bracket carrying the finger 31 and to the left thereof as viewed in Figures 1, '7 and 8.

Starting with the parts as shown in Fig. 2, and with the needle bar at the upper end of its stroke, when said needle bar moves downward, the outer end of the arm 25 will move downward faster than the downward movement of the arm 30. This will give slack to the needle thread preparatory to the needle entering the fabric and forming the needle loop therein. From the position shown in Fig. 3, the outer end of the thread arm 25 and the outer end of the thread arm 30, together with the thread eye 34, move downward together until the needle approaches the lower end of its stroke. This downward movement of the thread engaging members gives slack to the needle thread as they move toa position horizontally beneath the, thread guiding eye 24. When, however, the parts reach the position shown in Fig. 4, the thread eye 34 passes beneath the shoulder 38 (see Fig. 7) and the needle thread will be laid on this shoulder. Inasmuch as this shoulder is stationary, as it is carried by the bracket attached to the needle head, a continued downward movement of the thread eye 34 will cause a drawing up of the needle thread. The outer end of the thread arm 25 which has been moving downward substantially in unison with the outer end of the thread arm 30 will now begin to move upward, due to the fact that the link which reciprocates the needle bar is approaching a vertical position. This upward movement of the arm 25 does not give any ap preciable slack to the needle thread, for the reason that the arm 30 continues its downward movement with the arm 33 carrying the thread eye 34. This arm 30 continues with the arm 33 to draw on the needle thread until the needle reaches the lower end of its stroke. Furthermore, the slot 29 is elongated so that the upward movement of the arm 25 as the needle approaches the lower end of its stroke, does not give any appreciable added pull on the needle up the previous needle loop which has been dropped from the looper and produce a relatively tight setting of the stitches.

As the needle moves upward, there is a slight taking up action on the needle thread, but not sufficient to interfere with the needle throwing out its loop for the looper to enter. When the needle bar approaches the upper end of its stroke, then the arm 25 will move downward relative to the outer end of the arm 30, and the line between this arm 30 and the needle thread guiding eye 24. This gives up needle thread at the time when the feed of the fabric takes place. After the looper has entered the needle thread loop, the upward movement of the thread arms 25 and 30 which retain their position relative to each other during a considerable portion of the upward movement of the needle bar, will pull thread from the supply for the next stitch.

From the above description, it will be apparent that a thread controlling mechanism has been provided for the needle thread which is very simple and positive in its action as all of the moving parts are either fixed to the needle bar or fixed to the link which reciprocates the needle bar, and therefore, these parts must move in proper timing with the needle. Furthermore, a thread controlling means has been provided for the needle thread which pulls up on the needle thread as the needle approaches the lower end of its stroke, and this pulling up action on the needle thread continues until the needle has reached its full downward stroke.

While the needle thread controlling mechanism has been shown and described in connection with a specific type of sewing machine for securing a binding strip to the edge of a fabric section, it will be obvious that the needle thread controlling mechanism may be used in connection with any type of stitching mechanism for producing a two-thread lock chain stitch wherein the needle thread loops of a previous stitch can only be drawn up after the needle thread loop is shed fro-m the looper. It is also obvious that minor changes in the details of construction and the arrangement of the parts may be made without departing from the spirit of the invention as set forth in the appended claims.

Having thus described the invention, what I claim as new and desire to secure by Letters- Patent, is-

1. In a sewing machine, the combination of a needle, a needle bar, an operating shaft, a link connected to said operating shaft and said needle bar for reciprocating the same, thread controlling devices for the needle thread including an arm having a thread slot for the needle thread carried by said link, a stationary shoulder adjacent the path of reciprocation of the needle bar, a thread guiding eye carried by the needle bar and disposed so as to lay the needle thread over said shoulder as the needle approaches the lower end of its stroke, and a thread arm carried by the needle bar and having a thread slot in the outer end thereof disposed adjacent the path of reciprocation of the thread arm carried by the link and operating through its downward movement to take up the needle thread when said needle thread is released by the upward movement of the arm carried by the link as the needle approaches the lower end of its stroke.

2. In a sewing machine, the combination of a needle, a needle bar, an operating shaft, a link connected to said operating shaft and said needle bar for reciprocating the same, a stationary thread guide carried by the standard, a stationary thread shoulder carried by the needle head and located adjacent the path of reciprocation of the needle bar, a thread guiding eye carried by the needle bar and movable beneath said shoulder and adapted to pull up on said thread laid on said shoulder as the needle approaches the lower end of its stroke, a thread arm carried by the link 5 reciprocating the needle bar and having a thread slot in its outer end, said arm being disposed so as to engage the needle thread between the stationary thread guiding eye on the standard and the thread eye on the needle bar, and a thread 10 arm carried by the needle bar and disposed for reciprocation in a plane parallel with the plane of movement of the first-named thread arm and with its outer end adjacent the outer end of the arm carried by the link, said thread arm carried 15 by the needle bar being movable below a line through the, stationary thread guide on the standard and the thread shoulder on the needle head and operating to pull up on the needle thread as the needle approaches the lower end of its stroke 20 and to continue its pulling up action until the needle reaches the lower end of its stroke.

3. In a sewing machine having a needle actuating mechanism including a rotatable shaft, a reciprocal needle bar and a link connecting said 2 shaft and needle bar, the combination of needle thread controlling devices actuated by said needle actuating mechanism comprising a thread eye carried by and reciprocating with said needle bar, a fixed abutment disposed so as to engage the needle thread leading from said thread eye, whereby to exert an upward pull on the needle thread as the needle bar approaches its lowermost position and additional devices actuated in part by said needle bar and in part by said link for exerting an addi 35 tional upward pull on said needle thread at the same time as the pull is exerted by said thread eye and abutment.

4. In a sewing machine having a needle actuating mechanism including a rotatable shaft, a re- 4 ciprocal needle bar and a link connecting said shaft and needle bar, the combination of a needle thread controlling mechanism including a thread eye carried by and reciprocating with the needle bar, a fixed abutment disposed so as to engage the 45 needle thread leading from said thread eye whereby to exert an upward pull on the needle thread as the needle approaches the lower end of its stroke, and devices for exerting an additional upward pull on the needle thread at the same time comprising 50 a second thread eye mounted on and reciprocating with the needle bar, and a thread eye mounted on said link and moving in an orbital path therewith.

5. In a sewing machine having a needle actuating mechanism including a rotatable shaft, a re- 55 ciprocal needle bar and a link connecting said shaft and needle bar, the combination of needle thread controlling devices actuated by said needle actuating mechanism comprising a thread eye carried by and reciprocating with said needle bar, ,0 a fixed abutment disposed so as to engage the needle thread leading from said thread eye, whereby to exert an upward pull on the needle'thread as the needle bar approaches its lowermost position, and additional devices actuated in part by 55 said needle bar and in part by said link for exerting an additional upward pull on said needle thread at the same time as the pull is exerted by said thread eye and abutment, said additional devices also operating to pull off thread fromthe supply when the needle bar is in the vicinity of its uppermost position.

CHARLES F. RUBEL. 

